1. Field of the Invention
This invention relates to propulsion systems for underwater vehicles and, more particularly, to such systems designed to develop successive pulses of thrust by repeatedly filling a chamber and expelling the water therefrom at high velocity through one or more water jet nozzles.
2. Description of the Prior Art
Various attempts have been made in the past to develop thrust for propelling a vehicle by means of underwater thrust generators, some of which operate on principles akin to above-water rocket propulsion systems. Many of these are designed for hybrid systems, such as a boat or ship, in which the water jet propulsion device is of necessity located close to the surface of the water. Some depend upon extremely high through- or over-water speeds to develop a ram jet effect. These various prior art systems are exemplified in the Gongwer U.S. Pat. Nos. 2,714,800, 2,971,325 and 3,079,753; the Kemenczky U.S. Pat. Nos. 3,060,682 and 3,157,992; and in U.S. Pat. No. 3,107,486 of Linderfelt, No. 1,315,352 of Torazzi, No. 3,354,648 of Asahina, No. 2,938,481 of Maxwell et al, No. 2,351,750 of Fawkes, No. 3,163,980 of Turner, No. 3,137,997 of Kaminstein, No. 2,903,850 of Lang, No. 3,872,665 of Jarry, and No. 3,951,094 of Jastram et al.
In conjunction with the design of a new type of self-propelled anti-submarine weapon which is particularly directed to the destruction of submarines in relatively shallow water, an area which has heretofore presented problems which prevent the most effective utilization of currently known anti-submarine weapon systems, a particular type of underwater propulsion system is needed to propel the weapon at a reasonable average velocity while permitting a reduced velocity at periodic intervals to accommodate the needs of an effective sonar acquisition and tracking system. The present invention fills that need.